Steam automobile



Patented Sept. 29, 1925.

UNITED STATES PATENT OFFICE.

THOMAS BLACKADDER, 0F BAYSIDE, NEW YORK, AND HEB/BERT C. REED, OF STAM-FOLBJD, CONNECTICUT, ASSIGNORS .TO ROBESON PROCESS COMPANY, OF NEW YORK,

N. Y., A CORPORATION OF NEW JERSEY.

TANNING COMPOSITION.

No Drawing.

To all whom it may concern:

Be it known that we, THoMAs BLACK- ADDER and HERBERT C. REED, the formera citizen of the United States, and a resident of Bayside, in the countyof Queens and State of New York, and the latter being a citizen of theUnited States, and a resident of Stamford, in the county of Fairfieldand State of Connecticut, have invented certain new and usefulImprovements in Tanning Compositions, of which the following is aspecification.

This invention relates to tanning compositions; and it comprises as anew tanning and plumping composition a highly acid sulfite waste liquortanning preparation substantially free of acids foreign to such liquor,said preparation being distinctly acid to methyl violet as well as toother indicators, havin a high plumping power and being capab e ofbleaching iron-stained tanned hide; and it further comprises a method ofmaking such a preparation where in a sulfite waste liquor is made from asulfite liquor substantially free of magnesia and of bases other thanlime and is thereafter freed from lime with sulfuric acid or anotheracid capable of forming insoluble calcium salts; said waste liquor beingusually neutralized with pure lime and concentrated prior to the statedacid treatment; all as more fully hereinafter set forth and as claimed.

In the manufacture of paper pulp, one of the well known ways is todigest wood with a solution of sulfite liquor; an aqueous solution of anacid sulfite. This liquor can be made with sodium, calcium or magnesiumas a base, but generally dolomitic lime is employed and in this case theliquor contains the dissolved acid sulfites of both calcium and ofmagnesium. In the digestion, the acid sulfites mostly disappear as suchby reaction with organic matters of the wood; with the so-called lignonecomponent. The cellulose is left in insoluble form as paper pulp, whilethe lignone dissolves andforms, with the bisulfites, a solution of whatare often known as the lignosulfonates of the bases present. Thissolution separated from the paper pulp is cellulose sulfite wasteliquor.

As the liquor comes from the digester, it is of about 6 Baum specificgravity and is Application filed April 26, 1922. Serial No. 556,764.

of freely acid nature, although containing practically no sulfurous acidas such. The total amount of SO present, either as free acid or assulfites, is not often above 0.06 or 0.0.7 per cent. The acidity is inpart due to acetic acid and other weak acids. It may run as high as 0.75per cent acidity, calculated as free acetic acid. Commercially, the thinliquor is often neutralized with lime (dolomitic lime is mostly used)and evaporated to form a concentrated preparation. Such materials are onthe market and largely used for core binders, etc. Tanning preparationsare made from them by various methods, not here important. As stated,the original liquor is quite acid, and while usually probably most ofthe free acidity is due to acetic acid and similar weak organic acids,yet there are a number of stronger organic acids present in a state ofcombination with the bases (magnesia and lime). These acids, which arethe so-called lignosulfonic acids, vary in strength. Some of them are asweak as acetic acid but others, as shown by their influence on variousindicators, are to be classed among the strongest organic acids. Some ofthe lignosulfonic acids blue Congo paper and change methyl orangereadily, and some are still stronger, as is shown by their action onmethyl violet; an indicator responding only to the stron rest acids.Vhen the neutral concens tratec material is acidulated with a strongacid, as is sometimes done in making tanning preparations, the weakeracids are set free first.

e have found that these stronger organic acids, which (as free acids)have the power of greening a solution of methyl violet and which occurin the sulfiate waste liquor as calcium and magnesium salts, in a freestate are particularly advantageous tanning agents, being much better inthis respect than the weaker acids. They are also eflicient in plumpingand have an excellent solvent power for the lime of limed hides. And inaddition, they have the very desirable property of bleaching the darkand undesirable colors given leather by certain of the vegetable tanningagents, notably chestnut extract, in the presence of iron. Dark coloredleather tanned by chestnut extract is quickly hleached by these organicacids and these acids, used in connection with vegetable extracts whichwould otherwise produce dark leathers, give light colored products.

In the present invention it is our object to produce a tanningpreparation which shall contain in a free state all, or substantiallyall, of the natural acids of the sulfite waste liquor, including notonly the weaker acids but the stronger acids having the power ofgreening a solution of methyl violet; this preparation beingsubstantially free of bases and being also free of acids or othermaterials foreign to the sulfite waste liquor in its natural state; andto do this without injurious changes in the natural substances therepresent. Calcium sulfate is an insoluble body and by cautiously addingsulfuric acid to a sulfite waste liquor containing lime as its onlybase, it is possible to throw down as a precipitate of calcium sulfatenot only the lime but also the added acid. Practically nothing of amineral nature remains except for a trace of calcium sulfate in solutionor suspension. Both the lime acting as a base in the liquor and theadded sulfuric acid are removed together. While some of thelignosulfonic acids, as stated, have a very strong acidity,nevertheless, sulfuric acid will remove and precipitate the lime oftheir calcium salts. Instead of sulfuric acid, oxalic acid may beemployed; but we do not recommend this.

In order to have substantially only lime present as a base, the originalsulfite liquor used in digesting the wood should be made with a calcitelime, as free of magnesia as practicable. A little magnesia may be present, but it is desirable that the amount be as small as possible. If thesullite waste liquor be neutralized and concentrated prior to making ourproduct, as it usually is, neutralization should be done with calcitelime; that is, lime as free as practicable from magnesia. Instead ofusing lime as the base in making the sulfite liquor and in neutralizingthe sulfite waste liquor, baryta or strontia may be employed, but theuse of these bases under the present price conditions is not soadvantageous as the use of lime. Both baryta and strontia form sulfateseven more insoluble than calcium sulfate.

Neutralized sulfite waste liquor suffers no change in its organicconstituents injurious for the present purposes in evaporation underproper conditions and we may use either such a concentrated material orthe original weak liquor in the present invention. The former is themore advantageous, as it gives directly a comparatively concentratedmaterial, better suited for shipment, storage, etc., than the weakerproducts made from the original weak liquor.

In using the weak liquor, we simply add sulfuric acid in the amountequivalent to the lime present, thereby separating both the lime and theadded sulfuric acid as insoluble calcium sulfate. Ordinarily, after theaddition of the sulfuric acid, we allow the liquid to stand a few hoursin the cold to complete the precipitation. Vigorous stirring for a timeis advisable. The precipitate may be separated from the liquor by filterpressing or in other well known ways. This gives a liquor of freely acidnature but not containing foreign or extraneous acids. On addition of asmall amount of a solution of methyl violet, a distinct green color isattained. The acid liquor so obtained plumps hide very well, theplumping being about double that obtained with water. It is also anefficient agent in removing lime. It has an energetic tanning action. Ifapplied to hide tanned with chestnut extract and blackish or grayishbecause of iron-tan combinations, the leather is bleached. Ordinarily,however, we find it better to make a stronger preparation than can beobtained from the original weak liquor, and to this end we take the Weakwaste liquor made from sultite liquor with lime as the only base,neutralize with pure lime and concentrate, usually to 30 13., orthereabouts. The concentrated liquid is treated in the cold withcarefully added sulfuric acid, care being taken to avoid any heating up.The sulfuric acid is usually diluted with some water, and is added ascold as practicable. The concentrated sulfite liquor is also used coldand Vigorous agitation is resorted to and particularly in the laterstages of acidulation. The acid is best added in the exact amountrequired for combination with the lime present and acting as a base forthe lignosulfonic acids; allowance being made for such lime as may bepresent as calcium sulfate. A concentrated liquor of 30 13., made. asdescribed, ordinarily contains around 5 per cent of lime (Ca()) andrequires to 9 per cent by weight of sulfuric acid; 56 parts of CaOrequiring 98 parts of H 80 Starting with a 30 B. liquid, the newpreparation made is usually about 25 to 26 B.; the diminution in densitybeing partly due to the lime which has been removed and, usually, partlyto water added with the sulfuric acid. The 25 to 26 B. liquid is stableand can be packaged and shipped in the usual containers. Strongerpreparations can be made by using a concentrated sultite waste liquor ofmore than 80 15.; say, 32 to 33 13., but this is not so desirable. WVitha liquid of about 30 Baum giving a final strength of 25 or 26 15., it iseasier to separate the insoluble calcium sulfate by filtration. Ifstronger preparations are desired, the liquid can be concentrated byevaporation; but it is well to do this at the lowest possibletemperature, or even at the ordinary temperature. If concentration beresorted to, we do not ordi' narily desire to use a temperature of morethan, about 130 or 140 F. Cryogenic concentration is practicable.

\Vithout care in the addition of sulfuric acid, it is apt to burn orchange the liquid and especially in the later stages. It is for thisreason that we recommend the use of the acid somewhat diluted and ascold as practicable. The apparatus used may be provided with coolingmeans. \Vhile we have stated that we desire to make a preparation asfree from lime as possible and to this end usually add the exact, orsustantially exact, quantity of acid corresponding to the lime present,yet some of the advantages of our invention may be obtained with a lessquantity of sulfuric acid; i. e., with a little of the lime remaining.For example, instead of using about 8 or 9 per cent of sulfuric acidwith a 30 B. liquor, we may use 5 or 6 per cent. But the product is notnearly so advantageous as where enough acid is used to give a complete,or substantially complete, removal of bases. And there is a limit to theamount of lime which can be left in solution in combination with thesulfonic acids in securing a preparation of the properties we desire.lVith more than about 2.5 per cent of lime still present, starting withthe 30 B. liquor containing about 5 per cent lime, the preparation doesnot evince acidity when tested in a 1 per cent solution with methylviolet. The presence of lime in any substantial quantity isdisadvantageous. It renders the preparation less desirable as a tanning,plumping and de-liming agent.

A preparation made as stated from a concentrated liquor of 30 B. andhaving a density of 25 to 26 B., is substantially free of mineral basesor ash; not having to exceed about 1.2 per cent total ash. With aproperly made material, this ash represents, for the most part, calciumsulfate in suspension and solution. Its presence is immaterial. But, ifdesired, the quantity can be reduced somewhat by various expedients.\Vith quick work, the proportion of ash apt to be greater, some calciumsulfate coming out by after crystallizaton subsequent to filtration. Thepreparation is not only acid to methyl orange and Congo red, but also tomethyl violet. It is of course heavily acid to weak-acid indicators,such as phenolphthalein. It is free of sulfuric acid and other mineralacids and contains no acid foreign to sulfite waste liquor. It tans hideand may be used as a tanning material, alone or in admixture with othertanning agents. It mixes clearly with the various vegetable extracts,such as chestnut extract, quebracho extract, etc. As stated, used withsuch extracts it prevents discoloration of the hide, and used afterthem, it bleaches any dark color which they give the leather. Theorganic acids contained, while not in any way injurious to hidesubstance, will remove lime from it and will plump it very effectually.There is effected simultaneously with the plumping action, a tanningaction. The economy of simultaneous plun'lping and of effecting aconsiderable degree of tanning is, obvious.

In a typical preparation made under the present invention from aconcentrated neutralized sulfite waste liquor of 30 B. containing onlylime as a base, by the addition of the calculated amount of sulfuricacid and removal of calcium sulfate as far as practicable in quickoperation, the density was 26.5 B. Vith the particular concentratedsulfite liquor preparation used, this required about 8 per cent ofsulfuric acid. The liquid was practically free of mineral matter,containing only 1.20 per cent of which 0.90 per cent was calcium sulfatein suspension and solution. The acidity, as shown by titration in thepresence of methyl violet as an indicator, was 6.60 per cent (calculatedas acetic acid). Other indicators, such as Congo red andphenolphthalein, gave somewhat larger figuresrespectively 8.52 and 9.24per cent. The percentage of tans. was. 23.82 and that of non-tans 17.95, the purity being thus 57.0. In a 1 per cent solution, it gave 1.67times as much plumping action as water.

Typical preparations made in a similar way from light liquor(unconcentrated unneutralized digester liquors) have an analysis andproperties corresponding to that of the heavier preparations, such asthat just described. In either preparations made from light liquor orthose made from the heavier liquors, the total acidity, as shown bymethyl violet and calculated as acetic acid. is about 15 per cent of thetotal solids.

lVhat we claim is:

1. As a new tanning material a sulfite waste liquor preparation ofhighly acid nature, substantially free of acids foreign to sulfite wasteliquor, such preparation con taining free lignosulfonic acids ofstrongly acid properties, such acids causing an acidity of such a natureas to be shown by methyl 'violet as well as by other indicators.

2. As a new tanning material a sulfite waste liquor preparation ofhighly acid nature, substantially free of bases and ash components andof acids foreign to sulfite waste liquor, such preparation having anacidity of such a nature as to be shown by methyl violet as well as byother indicators.

3. As a new composition of matter, a waste sulfite liquor substantiallydevoid of ash constituents other than calcium sulfate and having itsacids in a free state; such preparation being free of mineral acids butcontaining in a free state organic acids capable of giving an acidreaction with Congo red and methyl violet; such prepara tion beingcapable of simultaneously plumping and tanning hide.

4. As a new tanning agent a sulfite liquor preparation of acid nature,such preparation having an acidity, expressed in terms of acetic acid,equal to about 15 per cent of the dissolved solids and beingsubstantially free of ash constituents other than calcium sulfate.

5. As a new tanning agent, a sulfite liquor preparation of acid naturegiving a distinct acid reaction with methyl violet and substantiallyfree of basic bodies other than lime.

6. As a new tanning agent, a sulfite liquor preparation of acid naturegiving a distinct acid reaction with methyl violet and substantiallyfree of basic bodies other than lime, the amount of lime not beinggreater than corresponds to 1.0 per cent calcium sulfate in apreparation containing about per cent solid matter.

7. As a new tanning agent, a sulfite liquor preparation containingsubstantially all the natural acids of sulfite waste liquor in a freestate but otherwise unchanged; said preparation being substantially frceof ash components other than calcium sulfate.

8. As a new tanning and leather bleaching agent a solution containing ina free state the stronger natural acids of sulfite waste liquor; suchpreparation being capable of giving an acid reaction with methyl violet.and of bleaching iron-stained vegetable tanned leather.

9. As a new tanning agent, a concentrated sulfite liquor preparation ofabout 25 degrees Baum and of distinctly acid nature to Congo red and tomethyl violet; such preparation being substantially free of magnesia andcontaining no free sulfuric acid.

10. In the manufacture of a tanning and plumping agent, the processwhich comprises precipitating a sulfite Waste liquor containingsubstantially only lime as a base with the amount of sulfuric acidcorresponding to the lime present in combination with organic acids andremoving the precipitate.

11. In the manufacture of a tanning agent, the process which comprisespreparing sulfite waste liquor with lime as substantially the only basepresent, adding sulfuric acid in amount sufficient to produce an acidreaction with methyl violet, the amount of sulfuric acid so added notbeing greater than that corresponding to the lime present, andseparating the calcium sulfate produced.

12. In the manufacture of a tanning agent, the process which comprisespreparing a concentrated waste sulfite liquor of about 30 Baum with limeas substantially the only base present, adding sulfuric acid in amountsuflicient to produce an acid reaction with methyl violet, the amount ofsulfuric acid so added not being greater than that corresponding to thelime present, and separating the calcium sulfate produced.

In testimony whereof, we have hereunto aflixed our signatures.

THOMAS BLACKADDER. HERBERT C. REED.

